blob: 02bb16a776cf4056ad24d4bf161e2d4a468dffc0 [file] [log] [blame]
// Copyright 2022 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// ffmpeg_md5sum wraps ffmpeg to reoutput MD5 sums from decoding, one per line.
package main
import (
const ffmpegPath = "/usr/local/bin/ffmpeg"
// multiFlags allow an alternative to passing space-separated flags, so that
// --f v1 v2 can instead be passed as --f v1 --f v2.
// The Golang flag package cannot parse space-sparated flags without enclosing
// the values in quotation marks. However, the platform decoding tests nest
// binary calls and flags, complicating quotations.
// This alternative provides a way to unnest/unfold the flags.
type multiFlags []string
// String implements the flag interface.
func (m *multiFlags) String() string {
return strings.Join(*m, " ")
// Set implements the flag interface.
func (m *multiFlags) Set(value string) error {
*m = append(*m, value)
return nil
// parseHashes parses hashes from ffmpeg output.
func parseHashes(stdout string) ([]string, error) {
lines := strings.Split(stdout, "\n")
hashes := make([]string, 0, len(lines))
for _, l := range lines {
l = strings.TrimSpace(l)
if len(l) == 0 || strings.HasPrefix(l, "#") {
tok := strings.Split(l, ",")
hash := strings.TrimSpace(tok[len(tok)-1])
if len(hash) != 32 {
return nil, errors.New(fmt.Sprintf("expected MD5 sum, got %v", hash))
hashes = append(hashes, tok[len(tok)-1])
return hashes, nil
// exitWithError dumps all output to the appropriate streams and exits with errcode 1.
func exitWithError(stdout, stderr string, err error) {
fmt.Fprintf(os.Stdout, stdout)
fmt.Fprintf(os.Stderr, stderr)
fmt.Fprintf(os.Stderr, err.Error())
func main() {
flag.Usage = func() {
"ffmpeg_md5sum is a wrapper around ffmpeg that generates MD5 sums from "+
"decoding, and processes that (annotated) output to output instead one "+
"hash per line.\n\n"+
"\tvideo: Required. Path to video to decode.\n"+
"\tflags: Optional. Additional flags to ffmpeg. Pass space-separated\n"+
"\t flags individually, i.e. `--flags -hwaccel --flags vaapi`\n"+
"\t to pass `-hwaccel vaapi` to ffmpeg.\n")
var flags multiFlags
var video string
flag.Var(&flags, "flags", "additional flags to ffmpeg: for space-separated flags, pass each individually with --flags")
flag.StringVar(&video, "video", "", "path to video to decode")
args := append(flags, []string{
"-loglevel", "verbose",
"-i", video,
"-vf", "format=pix_fmts=yuv420p",
"-f", "framemd5", "-",
ctx := context.Background()
cmd := exec.CommandContext(ctx, ffmpegPath, args...)
fmt.Fprintf(os.Stderr, "Running `%s %s`\n", ffmpegPath, strings.Join(args, " "))
var outbuf, errbuf bytes.Buffer
cmd.Stdout, cmd.Stderr = &outbuf, &errbuf
err := cmd.Run()
stdout, stderr := outbuf.String(), errbuf.String()
if err != nil {
exitWithError(stdout, stderr, err)
var hashes []string
if hashes, err = parseHashes(stdout); err != nil {
exitWithError(stdout, "", err)
fmt.Println(strings.Join(hashes, "\n"))